The field of telematics encompasses telecommunications, vehicle technology, on-road transportation, off-road transportation, and transportation safety. Telematics systems are applied to real time tracking of mobile assets such as motor vehicles, trailers, and shipping containers, and can be used to track a small number of mobile assets or an entire fleet of mobile assets. Technologies such as a satellite positioning system (e.g. GPS) allow the position of a mobile asset to be determined. Technologies such as wireless communication over wide area networks such as cellular telephone systems allow position information and other information to be relayed to a location that is remote relative to the mobile asset. Thus, it is feasible to monitor the location, movement, status and performance of mobile assets anywhere in the world.
Electronic components attached to vehicular or other assets often include a satellite transponder, global positioning system receiver, cellular modem, one or more sensors or transducers, a data storage device and a central computer or micro controller. These components are typically wired into fleet assets so that the location, usage and status of these assets can be remotely monitored. Collectively, these components gather position information from the GPS receiver, obtain input from multiple sensors or transducers regarding the condition of the asset, selectively store all or part of this data, and transmit selected data over the wireless network to a central dispatch location.
Certain environments present potential dangers to the use of electronic equipment, including electronic equipment associated with telematics systems. For example, refineries, chemical plants, mines and similar environments may present danger associated with potentially explosive mixtures of gases, liquids, aerosols, or particulate matter. Any electronic equipment used in these environments typically requires special attention to ensure that such equipment does not trigger an accidental explosion while operating, or under fault conditions. The technique of Intrinsic Safety has developed a recognized set of protection techniques for the safe operation of electrical equipment in hazardous areas by limiting the electrical energy available for ignition, i.e., preventing the formation of sparks or arcs. In essence, it is critical to ensure that electrical equipment does not adversely affect the safety of the environment in which it is used and that the equipment meets established safety standards and ratings, such as those published and endorsed by Underwriters Laboratory. The key operating principle in such system designs is to ensure that voltage and current levels present in the equipment remain within prescribed ranges.